1. Field of the Invention
The present invention relates to a bonding-to-each-other machine for bonding to each other a Fresenl lens sheet and a lenticular lens sheet that are used in a projection screen.
2. Description of the Related Art
In a projection screen, a Fresnel lens sheet and a lenticular lens sheet are disposed in the way they are superposed one upon the other. These lens sheets are manufactured respectively separately. Thereafter, the end surfaces thereof are regularly arranged and then superposed one upon the other. Thereby, the end surface portions are bonded to each other by means of a tape. Also, inspection is made of whether there are defects in the surface or interior of each lens sheet that has been created during the manufacture, or of whether the lens sheet has flaws created during its storage or a time period in which it is being handled.
However, each of the Fresnel lens sheet and the lenticular lens sheet is a product the size of that usually is as great as 40 to 80 inches. Accordingly, a significantly large length of time has hitherto been needed for the mutual tape bond process as well as for the inspection operation. In addition, the space that an apparatus for inspection occupies is as large as the size is non-ignorable. This has imposed a great limitation upon the disposition of the apparatus within the factory or the space for intermediate custody of the parts. Accordingly, there has been a demand for managing to reduce the time length, or the space, needed for the tape bonding or the inspection.
Thereupon, the present invention has been made under the above-described existing circumstances and has an object to provide a taping machine which enables shortening the time length for bonding to each other a Fresnel lens sheet and a lenticular lens sheet, as well as shortening the time length for the inspection process, and reducing the spaces occupied by the apparatuses for both the mutual tape bond process and the inspection process.
The present invention will hereafter be explained.
A first aspect of the present invention solves the above-described problems by providing a taping machine comprising a table part that can have placed thereon a Fresnel lens sheet and a lenticular lens sheet with the end surfaces thereof being regularly arranged and superposed over upon the other, and a tape-applying mechanism that bonds the end surfaces to each other by means of a tape.
According to this aspect, the tape-applying mechanism and the table part are constructed integrally with each other. Therefore, taping can be performed with the both lens sheets being fixed on the table part.
In this aspect, the table part may be constructed to have a black-colored opaque plate on which a transparent plate is mounted, and is thereby to be an inspection base that is for the purpose of finding out defects of the Fresnel lens sheet and the lenticular lens sheet.
According to this aspect of invention, the tape-applying mechanism and the inspection base are constructed integrally with each other. Therefore, while the end surfaces of the both lens sheets are being bonded together by the tape, it is possible to inspect the both lens sheets at least at anyone time (including combined times) of a time simultaneous with bonding to each other, a time immediately before bonding-to-each-other of them, and a time immediately thereafter. Also, because the two appliances are constructed integrally with each other, it is possible to achieve the reduction in space. Further, it is possible to execute by one operator the bonding process and the inspection process which have hitherto been carried out by two operators and therefore this can contribute to enhancing the productivity. Also, if the invention is constructed as above, it is possible for the operator to observe in a state where flaws or defects of each lens sheet are as if they were floated upwards from the black-colored opaque plate. So the operator does not overlook them and can highly efficiently perform the inspection operation. In addition, as a transparent plate is attached over the black-colored opaque plate, the black-colored opaque plate is prevented from being flawed by each of the both lenses. Therefore, it is possible to maintain the black color of the opaque plate over a long term.
Also, in this aspect, the tape-applying mechanism may be constructed in such a way as to include a nip unit that fixes the end surfaces of both lens sheet that are regularly arranged and superposed one upon the other, and a tape-applying unit that bonds to each other by means of the tape the end surfaces of the both lens sheets that are regularly arranged and superposed one upon the other.
If such is done like such, because the bonding process is performed with the both lens sheets being kept fixed, it is possible to bond the tape to the end surfaces of the both lenses reliably.
Also, in this aspect, it may be constructed in the way that the nip unit has a pair of fixing arms that, while a predetermined distance is being maintained from the end surfaces of the both lens sheets that are regularly arranged and superposed one upon the other, presses the both lens sheets from the obverse and reverse of a combined unit of the lens sheets. And on the surfaces of the paire of fixing arms at which they contact with the both lens sheets and the lenticular lens sheet there are mounted contact members each of that is formed of a material the hardness of that is lower than the material constituting the both lens sheets.
By constructing like that, it is possible to pinch the both lenses by and between the fixing arms and firmly fixing them. Also, because a material that is low in hardness is used on each of the contact portions between the fixing arms and the both lenses, flaws to be formed in the surface of each of the both lens sheets are prevented.
Further, in this aspect, it may be constructed in the way that the tape-applying unit includes a tape supply part that has a predetermined tape set thereto and supplies it, a tape-applying part that applies the tape it has received from the tape supply part to the end surfaces of the both lens sheets, and a moving mechanism that reciprocatingly moves the tape supply part and the tape-applying part along the end surface of the table part.
By employing such a construction, the tape that has been prepared beforehand can be bonded to the end surfaces of the both lens sheets while moving the tape along these end surfaces.
In the above-described aspect, the invention may be constructed in the way that the tape-applying part includes tape guides that draws out the tape from the tape supply part, pressing members that press the tape, which has been drawn from the tape guides, to the end surfaces of the both lens sheets, a pair of bending members that, regarding the tape having been pressed by the pressing members, bend the portion of that tape which has been stuck out from the end surfaces of the lens sheets, a pair of bonding members that, regarding the tape having been bent to the sheet side by the pair of bending members, pressure-bond this tape to the sheet side of the both lens sheets in the way the tape is pinched to the sheet surface side, and a cutter device that cuts the tape at a predetermined position.
In case the invention is constructed like that, the tape that has been drawn out from the tape supply part by means of the tape guides is pressed to the end surfaces of the both lens sheets by the pressing members. Both ends of the tape are bent to the sheet-surface side of the lens sheets by means of the pair of bending members. Further, those both ends of the tape are bonded to the sheet surfaces by means of the bonding members, and then is cut at a predetermined position by the cutter device. No operator""s time and labor are needed for executing the tape-applying operation. Accordingly, it is possible to achieve the automation of the tape-applying operation.
Also, in the above-described aspect, the invention may be constructed in the way that the moving mechanism includes a residual-amount-of-tape-alarming device that, when the residual amount of tape has become a predetermined value, rings an alarm.
If such is done like that, it is possible to prevent the residual amount of tape from running out in the mid-course of the the operation at the end surface, and to prevent such a situation where the operation is re-performed from occurring as a result of that.
Further, in the above-described aspect, the invention may be constructed in the way the moving mechanism is constructed so that the return speed thereof may be higher than the moving speed at the time of tape bonding.
If the invention is constructed like that, it is possible to further enhance the operating efficiency of the taping machine.
The above-described functions and advantages of the present invention will become apparent from the embodiment that will be explained next.